#include "ffcpp/ffcpp.h"
#include "ffcpp/MediaFile.h"
#include "ffcpp/Scaler.h"

namespace ff = ffcpp;

size_t KEY_FRAME_TO_SAVE = 0;

int main(int argc, char** argv) {
	ff::init();
	ff::MediaFile input(argv[1], ff::Mode::Read);
	ff::MediaFile output(argv[2], ff::Mode::Write);

	ff::Stream& vStream = input.videoStream();
	ff::Codec& vDecoder = vStream.codec();

	ff::Stream& outVStream = output.addVideoStream(AV_CODEC_ID_PNG, vDecoder.width(), vDecoder.height(), vStream.timeBase(), AV_PIX_FMT_RGB24);
	ff::Codec& vEncoder = outVStream.codec();

	output.writeHeader();

	size_t curKeyFrame = 0;
	ff::Scaler scaler(vDecoder, vEncoder);
	while(auto packet = input.readPacket()) {
		AVMediaType packetType = input.packetType(packet);
		if(packetType == AVMEDIA_TYPE_VIDEO) {
			auto frame = vDecoder.decode(packet);
			if(frame.isKeyFrame() && (frame.pts() > 0 || KEY_FRAME_TO_SAVE == 0)) {
				if(curKeyFrame == KEY_FRAME_TO_SAVE) {
					frame = scaler.scale(frame);
					frame.setPictureType(AV_PICTURE_TYPE_NONE);
					auto encPacket = vEncoder.encode(frame);
					if(!encPacket) continue;
					encPacket.setStreamIndex(0);
					encPacket.rescaleTimestamps(vStream.timeBase(), outVStream.timeBase());
					output.writePacket(encPacket);
					break;
				} else {
					++curKeyFrame;
				}
			}
		}
	}

	output.writeTrailer();

	return 0;
}